Osteomeles is a small genus of deciduous and semi-evergreen shrubs belonging to the rose family, Rosaceae, and placed within the order Rosales. The genus is native to eastern Asia, with species distributed across China, the Ryukyu Islands of Japan, and extending into the Pacific islands in the case of Osteomeles anthyllidifolia. Plants in the genus are characterized by pinnately compound leaves with an opposite arrangement on the stem, and they bear small pome fruits — the type of accessory fruit also found in apples and pears. A distinctive feature of the genus is that the fruits of all species are reported to be edible. Morphologically, Osteomeles has been compared to the South American genus Hesperomeles, as both share only one ovule per locule and hard seed-like pyrenes within the fruit. However, Hesperomeles bears simple rather than compound leaves, and recent molecular phylogenetic studies indicate the two genera are only distantly related despite this superficial similarity. The genus comprises a small number of accepted species, reflecting a restricted but ecologically interesting distribution across subtropical and temperate East Asia and the Pacific.
Distribution
Osteomeles shrubs are native to eastern Asia, with species occurring in China and the Ryukyu Islands of Japan (O. subrotunda, O. schwerinae). Osteomeles anthyllidifolia extends the range into the Pacific, including the Hawaiian Islands.
Taxonomy Notes
The genus has historically been compared to Hesperomeles of South America, as both share single ovules per locule and hard pyrenes. However, modern molecular phylogenetics indicate they are only distantly related; Hesperomeles is distinguished by its simple (not compound) leaves.
